At the start of
Chapter 2: The Search for El Dorado, continue forward along the path, and ignore the ledge on the right asking you to jump, and instead continue forward along the stream a short while. Keep an eye to your left, and you will find a sparkling object in a plant in the corner. Walk up to this object and press
to collect your first treasure, the
Silver Mosaic Inca Earring, which unlocks this trophy. (Although any treasure found will count as your first towards this trophy).
Thank you for positive votes! Please comment if I've made a mistake or you have anything to add. Stay tuned, as I'll be adding many more for Uncharted: The Nathan Drake Collection as I play and unlock them. Feel free to add me on PSN! Happy Hunting :)
-Kitty